docs: def allow_sync(self):
          """Allow sync queries within context. Close sync
          connection on exit if connected.
  
          Example::
  
              with database.allow_sync():
                  PageBlock.create_table(True)
          """
          old_allow_sync = self._allow_sync
          self._allow_sync = True
  
          try:
              yield
          except:
              raise
          finally:
              try:
                  self.close()
              except self.Error:
                  pass  # already closed
  
          self._allow_sync = old_allow_sync